After proper identification is made, the patient should be asked if diet restrictions were followed and if patient is taking any medications. Smoking, chewing gum (can contain sugar), or chewing tobacco should also be noted as certain analytes may be affected. Capillary blood collection may be difficult to obtain from chronic smokers because they have impaired circulation in the fingertips.
If diet restrictions were not followed or if patient is taking medications, the physician should be consulted before going any further since the results may be inaccurate. Some of the tests results affected include glucose, triglycerides, insulin, and iron among others.